As an example of a conventional method for reducing an amount of power consumption during the defrosting process in a refrigerator, a method in which exhaust heat generated in a compressor is accumulated in a liquid such as water, and the accumulated heat is circulated in the refrigerator through a pipe in a system other than the system of the cooling pipe, based on a pump, during the defrosting process, thereby defrosting an evaporator has been described in, for example, JP-A-2000-304415. FIG. 5 is a configuration diagram that shows the conventional way of reducing a power consumption in a defrosting heater described in JP-A-2000-304415.
In FIG. 5, a jacket 31 that a heat-accumulation agent is filled into is provided to cover a compressor 30 for compressing a refrigerant, and a pipe 32 for circuiting the heat-accumulation agent is connected to the jacket 31. A circulation pump 33, a heat-accumulation tank 34, and an electromagnetic valve 35 are connected to the pipe 32 in sequence, and thus, a closed system is formed therein. A defrosting chamber-circulation pipe 36 is connected to the circulation pump 33 and the electromagnetic valve 35 to be located between these members, and thus, a closed system is also formed therein.
In addition, an auxiliary heater 37 is provided around the heat-accumulation tank 34. Additionally, a three-way switching valve is used for the electromagnetic valve 35.
During cooling operation of the refrigerator, the electromagnetic valve 35 is opened to cause the heat-accumulation tank 34 and the jacket 31 to communicate with each other, and, a heat-accumulation agent (liquid such as water) is caused to circulate through the pipe 32 based on the circulation pump 33. The heat-accumulation agent is heated in the jacket 31 due to heat production in the compressor 30, the temperature of the heat-accumulation agent inside the heat-accumulation tank 34 is also gradually elevated. Accordingly, the exhaust heat produced in the compressor 30 is accumulated in the heat-accumulation tank 34.
When the refrigerator is switched to a defrosting-operation mode, the compressor 30 is switched off, the electromagnetic valve 35 is opened toward the chamber-circulation pipe 36, and the circulation pump 33 is activated to thereby cause the heat-accumulation agent to circulate through the chamber-circulation pipe 36, thereby carrying out the defrosting process. As needed, the auxiliary heater 37 is switched on to maintain the temperature of the heat-accumulation agent.
As another example of a conventional method for reducing an amount of power consumption in a defrosting heater in a refrigerator, a method in which a refrigerant is regurgitated from the compressor is described in, for example, JP-A-4-194564. FIG. 6 is a configuration view of a refrigeration cycle snowing the conventional method for reducing an amount of power consumption in a defrosting heater described in JP-A-4-194564. The arrows show a flow direction of the refrigerant (during the cooling operation).
The refrigeration cycle in FIG. 6 is configured by a compressor 43, a condenser 44, a capillary tube 45, and two evaporators (an evaporator 40, and an evaporator 42). A differential-pressure valve 46 is provided between the condenser 44 and the capillary tube 45, and an electromagnetic valve 41 is provided between the evaporator 40 and the evaporator 42.
During the normal cooling operation, the electromagnetic valve 41 is opened, and the refrigerant is caused to circulate therein while the pressure of the refrigerant is controlled based on the differential-pressure valve 46.
During the defrosting process (in which the compressor is switched off) the electromagnetic valve 41 is closed, and also, the differential-pressure valve 46 is closed. Accordingly, the high-pressure refrigerant gas regaining within the compressor 43 is regurgitated and flowed into the low-pressure evaporator 42, due to the pressure difference. Based on latent heat of condensation of the refrigerant gas, the defrosting process is carried out.
Furthermore, in general, compressors for compressing a refrigerant will exhibit reduced operation efficiencies when a suction temperature of the refrigerant becomes high, and therefore, such reduced operation efficiencies are suppressed based on an air-cooling or water-cooling system.